The steering wheel of a vehicle is developing from merely being a control element into a safety component with a complex requirements specification. Generally, the term ‘hand recognition’ (hands on/off detection) denotes the recognition of whether or not the driver's hands are located on the steering wheel rim of the steering wheel. In addition to increasing comfort, this detection is also associated with relieving the burden on the vehicle operator.
There are in principle two possibilities for creating a hands on/hands off sensing system. Firstly, it is possible to mount capacitive sensors on the steering wheel in order to establish whether the driver's hands are touching or respectively gripping the steering wheel. The second possibility is providing a torque sensor for measuring a steering wheel torque of the steering wheel, and analyzing a steering wheel torque signal produced by the sensor in order to establish whether the steering wheel is being steered by a driver.
Providing an inherent capacitive sensor for detecting manual guidance of a steering wheel is a relatively elaborate process and is consequently not suited to the mass production of vehicles. The possibility of analyzing a measured torque signal in order to recognize manual guidance of a steering wheel is relatively demanding. The signal produced by the torque sensor can oscillate relatively significantly, in particular as soon as the vehicle drives over potholes in the road or as soon as autonomous driving functions are enabled and assume control of the vehicle.